Method for removing contaminants from cannabinoid distillates

ABSTRACT

A method for removing contaminants such as pesticides and fungicides from cannabinoid extracts. Cannabinoid extracts containing contaminants may be dissolved in a water and ethanol solution, and then cooled to allow water-soluble contaminants to settle out of the mixture. The water and ethanol may then be removed via evaporation or distillation, leaving purified cannabinoids without contaminants. Contaminant removal may be incorporated into a method for producing a blended extract of cannabinoids and terpenes, which extracts terpenes using supercritical CO2, and extracts a cannabinoid concentrate from the residual material using a cold ethanol flush followed by distillation and then by contaminant removal; the CO2-extracted terpenes are then added back to the purified cannabinoid concentrate in a final blending step. Blending terpenes at the end of extraction may enhance the flavor and effectiveness of the purified cannabinoid concentrate.

This application is a continuation-in-part of U.S. Utility patentapplication Ser. No. 15/477,668 filed 3 Apr. 2017, which is acontinuation-in-part of U.S. Utility patent application Ser. No.15/410,289 filed 19 Jan. 2017, issued as U.S. Pat. No. 9,649,349, thespecifications of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

One or more embodiments of the invention are related to the field ofextraction of substances from plant material. More particularly, but notby way of limitation, one or more embodiments of the invention enable amethod for removing contaminants from cannabinoid distillates.

Description of the Related Art

Several methods for extracting cannabinoids from cannabis plant materialare known in the art. A limitation of many of these methods is that theterpenes in the cannabis plant are often lost or greatly reduced in thefinal extracted product. While cannabinoids provide a major element ofthe medicinal or psychoactive effect of cannabis, the many terpenes inthe cannabis plant also contribute significantly to the plant'sproperties.

Cannabis processors have explored techniques to simultaneously extractcannabinoids and preserve terpenes, with limited success. Processes andparameters that are optimal for cannabinoid extraction may beineffective for terpene extraction, and vice-versa. Moreover, tuning theratio of terpenes to cannabinoids is difficult or impossible whenattempting to extract both simultaneously. A potential solution to thesedifficulties, which is not known in the art, is to combine separateprocedures for terpene extraction and cannabis extraction, and to blendthe outputs of these procedures into a final product. This approachallows optimal processes and parameters to be used for each step, and itprovides maximum flexibility for the composition of the final blend.There are no known methods that use such an approach to generate aterpene-enhanced cannabinoid concentrate. In addition, the only methodknown in the art for terpene extraction is steam distillation, whichextracts a limited profile of terpenes because it is water based. Thereis a need for combining a more effective terpene extraction process witha blending process that combines terpenes and cannabinoids.

Existing methods for cannabis extraction may also fail to removecontaminants, such as pesticides and fungicides, from the extractedcannabis material. While some purification techniques are known, thereare no known methods that provide a simple and cost-effective processfor removing contaminants from cannabinoid distillates.

For at least the limitations described above there is a need for amethod for removing contaminants from cannabinoid distillates.

BRIEF SUMMARY OF THE INVENTION

One or more embodiments described in the specification are related to amethod for removing contaminants from cannabinoid distillates.Embodiments of the invention may be combined with an extraction processfor terpene oil and an extraction process for cannabinoids, to yield ablend with combined benefits of terpenes and purified cannabinoids.

One or more embodiments of the invention may produce a terpene-enhancedcannabinoid concentrate using the following steps: Cannabis plantmaterial is ground, then exposed to a carbon dioxide solvent, forexample using a supercritical CO2 fluid. The CO2 extracts terpene oiland terpene hydrosols from the cannabis. The residual plant material(after CO2 extraction) is then washed with cold ethanol, and theresulting ethanol oil solution is separated into ethanol (which may berecycled) and cannabis oil. The cannabis oil is then distilled to obtaincannabinoid distillates. These cannabinoid distillates are blended withthe terpene oil from CO2 extraction, yielding a terpene-enhancedcannabinoid concentrate. Terpenes may for example add flavor to thecannabinoid concentrate or enhance the effects of the concentrate.

Cannabinoid distillates may include any or all of THC, CBD, CBG, CBN,and THCV. In one or more embodiments, the concentration of cannabinoidsin the cannabinoid distillates may be 80% or higher. The cannabinoiddistillates may be optionally redistilled (multiple times if desired) toincrease the cannabinoid concentration.

Terpenes extracted in the terpene oil and terpene hydrosols may includeany or all of alpha-Bisabolol, Camphene, 3-Carene, beta-Caryophyllene,Citronellol, Cymene, Eucalyptol, Famesene, Fenchol, Geraniol, Guaiol,Humulene, Isopropyltoluene, Isopulegol, Linalool, delta-Limonene,beta-Myrcene, Nerolidol, alpha-Pinene, Ocimene, alpha-Terpinene,gamma-Terpinene, and Terpinolene.

Terpene oil and cannabinoid concentrate may be combined in any ratio. Inone or more embodiments, the ratio by volume of terpene oil tocannabinoid concentrate may be in the range of 1:25 to 1:5. In one ormore embodiments the ration may be in the range of 1:12 to 1:8. As anillustration, one or more embodiments may generate a blend with aterpene-to-cannabinoid concentrate ratio of approximately 1:10.

Illustrative parameters used for CO2 extraction of terpene oil andterpene hydrosol in one or more embodiments may include for example: CO2pressure in the range of 1000 psi to 1300 psi, forming a supercriticalfluid; temperature between 80 F and 100 F; and elapsed time of exposingthe cannabis plant material to the supercritical CO2 in the range of 15minutes to 6 hours. After CO2 extraction and removal of CO2 (for exampleby reducing pressure to allow the CO2 to evaporate), the terpene oil andterpene hydrosol may be filtered at a temperature between −80 F and 40F, using a filter with pore size greater than 0.25 micron.

Illustrative parameters used for cold ethanol extraction and ethanolrecovery in one or more embodiments may include for example: flushing ofresidual plant material with cold ethanol at a temperature of 30 F orbelow; and distilling the ethanol oil solution at a temperature between120 F and 165 F under a vacuum between 10 inches Hg and 25 inches Hg.Recovered ethanol may be optionally reused for subsequent washing of asecond batch of material.

Distilling of cannabis oil into cannabinoid distillates may be performedin one or more embodiments under vacuum with a pressure at or below 5torr. Cannabinoid distillates may be obtained at a temperature ofbetween 157 C and 230 C. In one or more embodiments, distillation mayalso yield terpene distillates, for example at a temperature between 140C and 157 C. Distillation of these products may be performed multipletimes to increase concentration or purity, followed by blending ofterpene oil with the cannabinoid distillates.

One or more embodiments of the invention may remove contaminants fromcannabinoid distillates or other cannabinoid extracts. Cannabinoiddistillates containing contaminants may be mixed with ethanol and water,and the contaminants may then be allowed to settle out of the solution.After separating the purified solution from the settled contaminants,the water and ethanol may be removed, leaving purified cannabinoiddistillates. This contaminant removal process may be used as astandalone process for purifying cannabinoid extracts, or it may beincorporated into the extraction and blending process described above.For example, contaminant removal may be performed after distillation andprior to blending of the cannabinoid distillates with terpenes.

Contaminants removed by one or more embodiments of the invention mayinclude for example, without limitation, pesticides and fungicides.These contaminants may be for example water-soluble. Illustrativecontaminants that may be removed using the invention include forexample, without limitation, Abamectin, Acephate, Acetamiprid, Aldicarb,Azoxystrobin, Bifenazate, Boscalid, Carbaryl, Carbofuran, Chlorpyrifos,Daminozide, Dichlorvos, Dimethoate, Ethoprophos, Fenarimol,Fenchlorphos, Fenhexamid, Fenoxycarb, Fipronil, Flonicamid, Fludioxonil,Fonofos, Imazalil, Imidacloprid, Iprodione, Kresoxim-methyl, Malathion,Metalaxyl, Methiocarb, Methomyl, MGK-264, Myclobutanil, Naled, Oxamyl,Paclobutrazol, Parathion, Phosmet, Piperonyl butoxide, Pirimiphos,Prallethrin, Promecarb, Propiconazole, Propoxur, Pyraclostrobin,Spinetoram, Spirotetramat, Spiroxamine, Tebuconazole, Thiacloprid, andThiamethoxam.

Illustrative parameters used in one or more embodiments for mixing ofcannabinoid distillates with water and ethanol may include for example:adding ethanol to cannabinoid distillates at a ratio between 2:1 and 4:1of ethanol by volume in mL to cannabinoid distillates by mass in grams;heating the cannabinoid-ethanol solution to a temperature between 40° C.and 80° C.; adding distilled water to the dissolved cannabinoid-ethanolsolution at a ratio between 1:4 and 1:10 of distilled water by volume inmL to cannabinoid distillates by mass in grams; and heating thecannabinoid-ethanol-water solution to a temperature between 40° C. and60° C.

Illustrative parameters used in one or more embodiments for allowingcontaminants to settle out of the cannabinoid-ethanol-water solution mayinclude for example: cooling the cannabinoid-ethanol-water solution to atemperature between −30° C. and 10° C.; and allowing contaminants tosettle out of the cooled solution for a period of time between 2 hoursand 7 days.

Illustrative methods used in one or more embodiments for separating thecannabinoid-ethanol-water solution into a purifiedcannabinoid-ethanol-water solution and the residual contaminants mayinclude for example: pouring the purified cannabinoid-ethanol-watersolution off of the cannabinoid-ethanol-water solution; siphoning thepurified cannabinoid-ethanol-water solution off of thecannabinoid-ethanol-water solution; and filtering the residualcontaminants out of the cannabinoid-ethanol-water solution.

Illustrative methods used in one or more embodiments for removingethanol and water from the cannabinoid-ethanol-water solution aftercontaminants have settled out may include for example: heating thepurified cannabinoid-ethanol-water solution to cause the ethanol andwater to evaporate; and distilling the purifiedcannabinoid-ethanol-water solution to recover the purified cannabinoiddistillates.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the inventionwill be more apparent from the following more particular descriptionthereof, presented in conjunction with the following drawings wherein:

FIG. 1 shows a high-level flowchart of an embodiment of a method forproducing a terpene-enhanced cannabinoid concentrate.

FIGS. 2 and 3 show a detailed flowchart of an embodiment of theinvention, illustrating steps, products, and optional flow paths in theprocess.

FIG. 4 shows illustrative equipment that may be used in the CO2extraction step of the process of FIG. 1.

FIG. 5 shows how the equipment of FIG. 4 relates to selected steps andproducts shown in the process flowchart of FIGS. 2 and 3.

FIG. 6 shows illustrative equipment that may be used in the cold ethanolextraction and ethanol recovery steps of the process of FIG. 1.

FIG. 6A shows a variation of the illustrative equipment of FIG. 6 forethanol recovery.

FIG. 7 shows how the equipment of FIG. 6 relates to selected steps andproducts shown in the process flowchart of FIGS. 2 and 3.

FIG. 8 shows illustrative equipment that may be used in the distillationstep of the process of FIG. 1.

FIG. 9 shows how the equipment of FIG. 8 relates to selected steps andproducts shown in the process flowchart of FIGS. 2 and 3.

FIG. 10 shows a variation of the flowchart of FIG. 1 that incorporate aprocedure for removing contaminants from cannabinoid distillates.

FIG. 11 shows an illustrative detailed flowchart for the contaminantremoval step of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

A method for removing contaminants from cannabinoid distillates will nowbe described. In the following exemplary description, numerous specificdetails are set forth in order to provide a more thorough understandingof embodiments of the invention. It will be apparent, however, to anartisan of ordinary skill that the present invention may be practicedwithout incorporating all aspects of the specific details describedherein. In other instances, specific features, quantities, ormeasurements well known to those of ordinary skill in the art have notbeen described in detail so as not to obscure the invention. Readersshould note that although examples of the invention are set forthherein, the claims, and the full scope of any equivalents, are whatdefine the metes and bounds of the invention.

FIG. 1 shows a high-level flowchart of an embodiment of the invention.The steps shown are illustrative; one or more embodiments may useadditional steps, or a subset of the steps shown. One or moreembodiments may perform these steps in any desired order. One or moreembodiments may perform one or more of these steps in parallel. Theprocess shown in FIG. 1 generates a cannabinoid extract 112 that isenhanced with terpenes. Addition of terpenes to the cannabinoid extractmay add flavor and may introduce compounds into the final blend that mayhave beneficial effects. The process may be performed at any scale,ranging for example from a micro scale such as on a benchtop to a largeindustrial scale such as in a refinery.

In the illustrative flowchart of FIG. 1, raw cannabis material 101 isobtained and is input into the grinding step 102. Cannabis material 101may include for example, without limitation, the leaves, flowers, orbuds of one or more cannabis plants. The flowers or buds have thehighest concentration of cannabinoids and terpenes; however, any part orparts of the cannabis plant may be processed. The grinding step 102 mayuse any grinding method or methods, such as hand grinding, machinegrinding, or use of a chipper or mulcher. In one or more embodiments,the grinding step may grind the material to a particle size similar tothat of typical coffee grounds. Initial grinding may be followed in oneor more embodiments by one or more filtering stages, for example tofilter out stems or sticks. An illustrative mesh size used in one ormore embodiments for filtering may be in the range of ¼ inch to ½ inch.

Grinding step 102 may be followed by CO2 extraction step 103. This stepmay be used for example to extract a terpene oil 104 from the groundplant material; some or all of this oil may be added back into therefined material in a later stage, as illustrated in blending step 111in FIG. 1. CO2 extraction may for example extract terpenes moreeffectively and completely from cannabis material than the steamdistillation process that is generally used for terpene extraction. CO2extraction 103 may for example use a supercritical CO2 fluid. In thisprocess CO2 is pressurized to form a liquid, and the liquid is mixedwith the ground cannabis material to extract the desired compounds (inthis case, terpenes). The CO2 may be removed from the solution byreducing the pressure, which allows the CO2 to evaporate as a gas andleaves the terpene extract behind. Illustrative process parameters usedin one or more embodiments for the CO2 extraction step include: CO2pressure in the range of 1000 psi to 1300 psi for the extraction;extraction temperature in the range of 80 F to 110 F; and separationtemperature (after extraction) in the range of 40 F to 70 F. Run timefor the CO2 extraction step may be for example in the range of 15minutes to 6 hours.

After the extraction into the CO2 solution, terpene oils and hydrosolsmay be harvested from the solution. The oil may contain for example amixture of terpenes and some cannabinoids, and the hydrosol may containwater-based terpenes and water. After removing the CO2 (via evaporation,for example), the remaining solution may be separated by allowing it tosettle until the oil and the hydrosols separate, and then bleeding offthe hydrosols. These products may then be filtered to remove waxes andcannabinoids by chilling them to a temperature in the range −80 F to 40F, and then filtering with a coffee filter or a lower micron filter, forexample with a pore size above 0.25 microns. Terpene oil 104 extractedin step 103 may be useful as a separate product (such as an essentialoil), or it may be blended into further cannabinoid extracts in blendingstep 111.

Terpenes present in the extracted terpene oil and terpene hydrosol mayinclude for example, without limitation, any or all of the terpenesalpha-Bisabolol, Camphene, 3-Carene, beta-Caryophyllene, Citronellol,Cymene, Eucalyptol, Famesene, Fenchol, Geraniol, Guaiol, Humulene,Isopropyltoluene, Isopulegol, Linalool, delta-Limonene, beta-Myrcene,Nerolidol, alpha-Pinene, Ocimene, alpha-Terpinene, gamma-Terpinene, andTerpinolene. Hydrosols may include primarily humelene and pinene, butany other terpenes may also be present in the hydrosols. Typical terpeneconcentration in hydrosols may be in the range of 1% to 10%, whiletypical terpene concentration in terpene oil may be up to 99%. Hydrosolsand oil may also include some cannabinoids, for example up to 15%cannabinoids in terpene oils and up to 5% in hydrosols. The terpene oiland terpene hydrosols may be used for example as flavoring, or in aromatherapy products, in salves, in creams, or in topical treatments. Theseterpene compounds may have medicinal uses when taken internally orapplied externally.

After extracting terpenes in step 103, the remaining non-extracted plantmaterial may then be processed in cold ethanol extraction step 105. Forexample, the plant material that was exposed to the CO2 may be emptiedfrom the CO2 extraction vessel and placed into one or more sanitarysteel tubes, which may then be placed into a cryogenic freezer or othercooling apparatus to cool the plant material to a temperature in therange of −80 F to 30 F. Each tube may then be attached to a catch pot,possibly with a filter between the tube and the catch pot, and coldethanol may be introduced into the tube and exposed to the plantmaterial. After exposure, a dump valve may be opened to allow the coldethanol solution to flow into the catch pot. A vacuum may also beapplied to facilitate removal of the cold ethanol solution from thetube. The tube may be flushed for example for a time in the range of 5minutes to 30 minutes. Flushing may continue for example until theethanol stops or until it begins to turn greenish in color. The catchpot then contains an ethanol oil solution with extracted compounds fromthe plant material.

The ethanol oil solution may then be processed in ethanol recovery step106 to remove some or all of the ethanol from the solution, leaving acannabis oil product 108. As illustrated in FIG. 1, some or all of therecovered ethanol 107 may be recycled into the cold ethanol extractionstep 105. The ethanol recovery process may for example use a vacuumdistillation method to remove ethanol from the solution. The ethanol oilsolution may be transferred into a recovery column which may be warmedin a water bath or in a jacketed column, for example to a temperature inthe range of 120 F to 165 F. The recovery column may be connected to acondenser with circulating cold water and connected to a vacuum toaccelerate ethanol evaporation. In an illustrative ethanol recoveryprocess, after starting the cold water circulation the vacuum pump levelmay be set in the range of −10 inches Hg to −25 inches Hg. Condensedethanol may be recovered into a container, which may then be used asinput to the cold ethanol wash step for subsequent batches. Recovery runtime may for example range from approximately 30 minutes to 3 hours,yielding recovered ethanol at a rate of approximately 7.5 L to 10 L perhour.

The remaining oil in the recovery column after the ethanol recovery stepis an organic cannabinoid concentrated oil 108. This oil may be referredto colloquially (although not completely correctly) as “Rick SimpsonOil,” or “RSO.” It may contain for example cannabinoids in aconcentration of approximately 50% to 90%, and may contain for exampleup to 20% terpenes. Cannabinoids contained in the oil may include forexample, without limitation, THCa, THC, THCV, CBDa, CBD, CBC, CBG, andCBN. The oil may be processed further to form a concentrate (asdescribed below), or it may be used directly as a final product. The oilmay be smoked or vaped, for example as a “shatter” or in a vape pen asan oil. It may be activated, for example by heating in an oven toapproximately 180 F, and incorporated into edible products, topicals,creams, or salves.

The cannabis oil 108 may then be further concentrated in distillationstep 109. Distillation 109 may for example use any distillation devicesand techniques, including for example, without limitation, short pathdistillation, thin film distillation, wipe film distillation, andspinning band distillation. An illustrative distillation process is asfollows. The cannabis oil 108 is placed on a hot plate with a stir rodor stir bar, at a temperature of no more than 140 C in one or moreembodiments. Distillation may be performed under vacuum or withoutvacuum. With a vacuum under 5 torr, most terpenes distill out before 157C; cannabinoid distillates 110 distill out between 157 C and 185 C; andsome additional products such as CBG, CBN, and THCV distill out between185 C and 230 C. Without a vacuum, distillation may be performed forexample between 370 C and 440 C. In one or more embodiments, theproducts of distillation may be redistilled, possibly multiple times, toincrease the concentration of the final product. The cannabinoiddistillates 110 may for example have cannabinoid concentrations between80% and 99.99%, with higher levels possible using multipledistillations. Cannabinoid distillates may be smoked or vaped, forexample as a “shatter” or in a vape pen as an oil. They are alreadyactivated as a result of the distillation process; therefore, they maybe incorporated into edible products, topicals, creams, or salves.

In one or more embodiments, the cannabinoid distillates 110 may beblended in step 111 with the terpene oil 104 extracted using CO2extraction 103, to create a terpene-enhanced cannabinoid concentrate112. This blending may for example add flavor and may create additionaleffects when smoking, vaping, or ingesting the blend. Blending terpeneoil with the cannabinoid distillates may also make the product 112 thinenough to be used in vape pens. In one or more embodiments, the blendingstep 111 may use a ratio by volume of terpene oil to cannabinoiddistillates in the range 1:25 to 1:5. An illustrative embodiment may usefor example a ratio of terpene oil to cannabinoid distillates of 1:10.

FIGS. 2 and 3 show a more detailed flowchart of an embodiment of theinvention. (FIG. 3 is a continuation of FIG. 2). Cannabis material 101is input into grinding step 102, yielding ground/sifted material 202 a.This material 202 a is then filtered to remove sticks, stems, and stalks202 c. The remaining ready plant material 202 b is input into the CO2extraction process. If needed or desired, additional grinding, sifting,and filtering may be performed on either or both of the sticks, stems,and stalks 202 c, and the ready plant material 202 b, prior to CO2extraction. Unused stems, sticks and stalks 202 c are dried and baggedinto waste products 202 c, and sent to a waste disposal/compostingprocess 220.

The material 202 b is then loaded into a CO2 extraction vessel, formingloaded material 103 a. Terpene extraction 103 b is then performed usingCO2 203 b as a solvent. This extraction yields terpene oil 104 andterpene hydrosols 104 b. The remaining dry plant material 203 a isfurther processed with the next steps in the process. CO2 203 b removedfrom the solution may be recycled and used for additional terpeneextraction steps 103 b.

The cold ethanol extraction process then proceeds with dry plantmaterial 203 a placed into a container and cryogenically frozen,yielding frozen material 205 a. Ethanol wash 205 b is then performedover this frozen material, yielding ethanol concentrate solution 205 c.The remaining soaked plant material 205 d may be reprocessed withadditional cryogenic freezing 205 a and ethanol wash 205 b if desired,or formed into waste material 205 e that is transmitted to wastedisposal/composting process 220. The solution 205 c is then transferredto a solvent recovery vessel 206 a, and ethanol recovery process 106removes ethanol 107 from the solution. The ethanol may be recycled ifdesired for subsequent cold ethanol extraction steps. After removingethanol, the solution contains plant concentrate oil 108 a.

Turning now to FIG. 3, which is a continuation of FIG. 2, plantconcentrate oil 108 a (“C” from FIG. 2) may be used directly as cannabisoil 108 (also referred to colloquially as “RSO”). It may also be furtherprocessed with distillation and blending. Oil 108 may be placed in adistillation vessel 309 a. In addition, if desired, some or all of theethanol 107 removed from the oil (“B” from FIG. 2) may be furtherdistilled to obtain any residual cannabinoids or other products.Molecular distillation steps 109 may yield various fractionallydistilled products 309 b (for example at different distillationtemperatures), including cannabinoid distillates 110 and isolatedterpenes 309 a. Remaining plant material 309 d after distillation toextract products 110 and 309 c may be transformed into waste 309 e anddisposed in step 321, or it may be redistilled. Products 110 and 309 cmay also be redistilled, for example to increase product concentration.Cannabinoid distillates 110 may then be blended with the terpene oil 104from CO extraction (“A” from FIG. 1), yielding terpene-enhancedcannabinoid oil 112.

FIGS. 4 through 9 show illustrative equipment that may be used in one ormore steps of the process in one or more embodiments of the invention.This equipment is illustrative; one or more embodiments may use anydesired equipment for any step or steps. Any of the steps may be manual,automated, or semi-automated. FIG. 4 shows illustrative equipment thatmay be used for CO2 extraction in one or more embodiments of theinvention. CO2 extraction may for example use an Apeks® 1500-20LBotanical Oil Extraction System, or any similar equipment. FIG. 4 showsselected components of the system; it does not show all components andall connections. CO2 gas is obtained from CO2 tank 401. This gas flowsto chiller 402, which cools the gas using heat exchanger 403. Thepressure of the gas is increased with compression pump 404, yielding asupercritical CO2 fluid. This fluid is passed over ground and frozencannabis material in extraction vessel 405. The CO2 solution withextracted terpenes then flows to separation vessel 406, which has acollection cup 407 at the bottom. The CO2 evaporates from vessel 406,leaving the terpene oil and hydrosols in collection cup 407. If desiredor needed, further separation may be performed using separation vessel408.

FIG. 5 annotates the equipment of FIG. 4 with selected process steps andproducts from the flowchart of FIGS. 2 and 3. After grinding 102,material 103 a is loaded into the CO2 system in extraction vessel 405.The products of CO2 extraction including terpene oil 104 and terpenehydrosols 104 b are collected in collection cub 407. After CO2extraction, the plant material 203 a remaining in vessel 405 is removedand is transferred to cold ethanol extraction step 105, which isdescribed next.

FIG. 6 shows illustrative equipment that may be used for cold ethanolextraction in one or more embodiments of the invention. Frozen plantmaterial is placed into tube 601, which is flushed with cold ethanol.The cold ethanol solution containing extracted compounds is drained intoreceiving vessel 602, assisted by a vacuum. The vacuum pump 611 pullsair through line 621 to a connection at the top of vacuum cold trap 610,and from the cold trap through line 622 to the pump. The ethanolsolution is then transferred to container 603, which is placed into hotwater bath 605. The hot water bath is heated by heating element 604. Theheat causes the ethanol in the solution to evaporate; ethanol vaporreaches condenser 606 which is cooled by cold water flowing from coldsolution bath 608 through water line 631, and then returned via line 632to the cold bath 608. Water flow is driven by pump 609 in the coldsolution bath. Distillation of ethanol is vacuum assisted with vacuumline 623 attached to receiving vessel 607 that collects condensedethanol. An additional vacuum cold trap 610 captures residual ethanolthat may be in the vacuum line.

FIG. 6A shows another embodiment of equipment that may be used forethanol recovery. In this embodiment, the equipment is mounted on rack6A30, for example to comply with building and health codes. Theequipment arrangement in FIG. 6A may also support more efficientoperation than the arrangement of FIG. 6; for example, a batch ofmaterial may be processed using the embodiment of FIG. 6A inapproximately 10 minutes, as compared to approximately an hour using theequipment configuration of FIG. 6. Efficiency improvements are achievedfor example by providing mechanisms for the input of material and outputof products without requiring equipment to be disassembled, reassembled,moved, or transferred. For example, the embodiment of FIG. 6A adds afeed spout 6A40 for container 603, so that users can add more materialto the oil base without having to dismantle equipment. It also addsjacketed collection bottoms to each of the collection bases, whichallows for material harvesting directly off the system withoutdisassembling the equipment. A spout is attached to each collectionbottom for harvesting of material: spout 6A41 may be used for harvestingof oil from collection vessel 603; spout 6A42 may be used for harvestingof ethanol from vacuum cold trap 610; and spout 6A43 may be used forharvesting of ethanol from recovered ethanol receiving vessel 607.

As in the embodiment of FIG. 6, an ethanol solution added to container603 after frozen plant material has been washed with cold ethanol toextract plant compounds into the ethanol solution. In the embodimentshown in FIG. 6, container 603 is placed in a hot water bath. In theembodiment shown in FIG. 6A, a separate hot water reservoir 605 a isused and hot water is pumped along water lines to a jacket surroundingcontainer 603, thereby heating the ethanol solution and generatingethanol vapors that are recovered. For example, in the embodiment shownin FIG. 6A, hot water flows from reservoir 605 a along water line 6A01to a jacket surrounding container 603, and then along water line 6A02 toa jacket surrounding the collection bottom of container 603, and thenalong water line 6A03 back to the hot water reservoir 605 a. As in theembodiment of FIG. 6, ethanol vapors reach condenser 606, and condensedethanol flows to recovered ethanol receiving vessel 607. In theembodiment of FIG. 6, receiving vessel 607 is placed in a cold waterbath. In the embodiment shown in FIG. 6A, a separate cold waterreservoir 608 a is used. Cold water is pumped along water lines fromreservoir 608 a to the condenser and to a jacket surrounding the ethanolreceiver. Also as in FIG. 6, there may be an additional vacuum cold trap610 to capture residual ethanol that may be in the vacuum line, but inFIG. 6A this vacuum cold trap receives cold water along water linesrather than being placed directly in a cold water bath. In theembodiment of FIG. 6A, cold water flows along water line 6A11 from thecold water reservoir 608 a to the condenser 606, then along line 6A12 toa jacket surrounding recovered ethanol receiving vessel 607. The coldwater then flows along line 6A13 to a jacket surrounding the collectionbottom of the receiving vessel 607. Cold water then flows along line6A14 to a jacket surrounding vacuum cold trap 610, then along line 6A15to a jacket surrounding the collection bottom of the vacuum cold trap,and then along line 6A16 to return to the cold water reservoir 608 a.Vacuum pump 611 provides a vacuum, with vacuum lines 6A22 and 6A21connecting the vacuum pump to the vacuum cold trap 610 and to therecovered ethanol receiving vessel 607. The specific configuration androuting of the air and water lines shown in FIG. 6A are illustrative;one or more embodiments may route and configure these lines in anydesired manner. One or more embodiments may use continuous sources ofhot or cold water instead of or in addition to water reservoirs asillustrated in FIG. 6A.

FIG. 7 annotates the equipment of FIG. 6 with selected process steps andproducts from the flowchart of FIGS. 2 and 3. Material 205 a that iscryogenically frozen is placed into tube 601. Ethanol 107 is added tothe tube and cold ethanol extraction step 105 removes the ethanolconcentrate solution 205 c from tube 601 into receiving container 602.This solution 205 c is then transferred to container 603 as solution 206a for solvent (ethanol) recovery. Ethanol recovery step 106 occurs incondenser 606 (and possibly in vacuum cold trap 610 as well) as ethanolvapor condenses, and recovered ethanol is collected in container 607(and possibly in container 610). This recovered ethanol 107 may berecycled for additional cold ethanol flushes of material in tube 601.The material remaining in container 603 after ethanol recovery iscannabis oil 108.

FIG. 8 shows illustrative equipment that may be used for cannabis oildistillation in one or more embodiments of the invention. This figureshows a short path distillation process; one or more embodiments may useany desired distillation process, including but not limited to shortpath distillation. Flask 801 containing cannabis oil is placed onheating element 802. Distillation head 803 attached to flask 801 has anattached thermometer 804, and has connections for vacuum and water.Water line 821 provides cooling water to the condenser water jacket 805from water source 806, and return water line 822 drains or recirculatesthis water. Vacuum line 831 attaches connection 807 to vacuum pump 809,and vacuum line 832 attaches to connection 808 on distribution bulb 811.In this illustrative embodiment, three collection flasks 810 a, 810 b,and 810 c are attached to distribution bulb 811.

FIG. 9 annotates the equipment of FIG. 8 with selected process steps andproducts from the flowchart of FIGS. 2 and 3. Cannabis oil placed indistillation 309 a is placed in flask 801. Molecular distillations 109occur in distribution head 803, and distillation products such ascannabinoid distillates 110 and isolated terpenes 309 c are collected incollection flasks 810 a, 810 b, or 810 c. Thermometer 804 may be used tomonitor the distillation temperature in order to separate and identifyproducts such as cannabinoid distillates 110 and terpene distillates 309c that distill out at different temperatures.

One or more embodiments of the invention may include techniques or stepsto remove contaminants from a cannabis extract. These contaminants mayinclude for example, without limitation, pesticides or fungicides.Contaminant removal procedures may be applied to any cannabis extract.These procedures may be combined with the steps and methods describedabove for extracting cannabis and blending the extract with terpenes.Contaminant removal procedures may also be used as independentstandalone methods to purify any cannabis extract, regardless of how theextract was obtained and regardless of how the purified extract is usedafter purification.

FIG. 10 shows an illustrative variation of the flowchart of FIG. 1 withcontaminant removal step 1001 incorporated into the flowchart. In thisillustrative flowchart, contaminant removal is performed on cannabinoiddistillates 110, which are the product of distillation step 109performed on cannabis oil 108. One or more embodiments of the inventionmay insert a contaminant removal step at any other point or points in anextraction process pipeline, and potentially at multiple such points. Inthe flowchart of FIG. 10, the purified cannabinoid distillates obtainedas the output of step 1001 are input into blending step 111, which mayfor example add terpene oil 104 to the purified cannabinoid distillates.In one or more embodiments of the invention, the purified cannabinoiddistillates output from contaminant removal step 1001 may be a finalproduct, or they may be further processed in any desired manner.

FIG. 11 shows an illustrative detailed flowchart for an embodiment ofcontaminant removal process 1001. These contaminant removal steps may beincorporated into an extraction and blending process, as illustrated inFIG. 10, or used standalone for any cannabinoid extract. The stepsillustrated in FIG. 11 may be used for example with contaminants such aspesticides and fungicides that are water soluble. Since mostcannabinoids (such as for example THC, CBD, CBC, CBG, and CBN) are notvery soluble in water, mixing cannabinoid distillates 110 in water maybe an effective method for separating contaminants from thecannabinoids. This process works effectively for water-solublecontaminants, which includes many pesticides and fungicides. Forexample, without limitation, the steps of FIG. 11 may be used withwater-soluble contaminants such as Abamectin, Acephate, Acetamiprid,Aldicarb, Azoxystrobin, Bifenazate, Boscalid, Carbaryl, Carbofuran,Chlorpyrifos, Daminozide, Dichlorvos, Dimethoate, Ethoprophos,Fenarimol, Fenchlorphos, Fenhexamid, Fenoxycarb, Fipronil, Flonicamid,Fludioxonil, Fonofos, Imazalil, Imidacloprid, Iprodione,Kresoxim-methyl, Malathion, Metalaxyl, Methiocarb, Methomyl, MGK-264,Myclobutanil, Naled, Oxamyl, Paclobutrazol, Parathion, Phosmet,Piperonyl butoxide, Pirimiphos, Prallethrin, Promecarb, Propiconazole,Propoxur, Pyraclostrobin, Spinetoram, Spirotetramat, Spiroxamine,Tebuconazole, Thiacloprid, and Thiamethoxam.

In step 1101, cannabinoid distillates 110 are mixed with ethanol 1102and then warmed to allow the distillates to dissolve. Any type ofcontainer of any size may be used to mix the distillates, the ethanol,and the water (described below), such as for example a beaker or a masonjar. Any type of heat source may be used to warm the solution, includingfor example, without limitation, a hot plate, a warm water bath with aSous Vide cooker, a Cascade Sciences TVO-2B Vacuum Purge Oven, and aThermo Scientific Heratherm 51029336 Advanced Security Incubator (forexample 24.8 cu ft. SS, Dual; 120V).

In one or more embodiments of the invention, ethanol 1102 may be mixedwith cannabinoid distillates 110 in a ratio between 2:1 and 4:1 ofethanol by volume (in mL) to cannabinoid distillates by mass (in grams).The mixture may be warmed for example to a temperature between 40° C.and 80° C. to allow the cannabinoid distillates 110 to dissolve intodissolved distillate 1103.

In step 1104, distilled water 1105 is added to dissolved distillate1103. In one or more embodiments of the invention, distilled water 1105may be mixed with dissolved distillate 1103 in a ratio between 1:4 and1:10 of water by volume (in mL) to cannabinoid distillates by mass (ingrams). The mixture may be warmed for example to a temperature between40° C. and 60° C. Heat sources such as those described above may beused. The distillate then breaks down with the water and the ethanol.

The dissolved solution of cannabinoid distillate, ethanol, and water isthen cooled in step 1106. In one or more embodiments, the solution maybe cooled to a temperature between −30° C. and 10° C. Any desired coldsource may be used, including for example, without limitation, arefrigerator, an ice bath, a freezer, snow, or dry ice.

In step 1107, the cooled distillate-ethanol-water solution is left inthe cooled environment for a period of time to allow the densermolecules of the water-soluble contaminants to settle out of thesolution. These contaminants will sink to the bottom of the containerunder gravity over time. In one or more embodiments, the solution isallowed to settle for a period of time between 2 hours and 7 days.

In step 1108, the now purified solution is separated from thecontaminants that have settled to the bottom. This separates the mixtureinto contaminants 1111 and the dissolved clean distillate 1110. Thesecomponents may be separated by various techniques, including forexample, without limitation, pouring the clean solution off the top ofthe container into a clean beaker, siphoning the clean solution off thetop of the container into a clean beaker, or filtering the contaminantsout of the solution. Filtering options may include for example, withoutlimitation, filtering with a coffee filter, filtering with a Buchnerfunnel and filter paper (0.025 micron to 10 micron) with or withoutvacuum assist, and using a separator funnel. The removed contaminants1111 are sent to a waste disposal process 1112, for example in a sealedjar or other hazardous material container.

Dissolved clean distillate 1110 is then processed in step 1115 to removethe ethanol and water that were added in steps 1101 and 1104, leavingthe purified cannabinoid distillates 1120. Removal of water and ethanolmay be done for example, without limitation, by heating the mixture 1110(for example on a hot plate) to burn off the water and ethanol, or bydistilling the mixture 1110 to recover the cannabinoid distillates (forexample, using a short path distillation apparatus). In one or moreembodiments, the purification process may be repeated as many times asnecessary or desired to achieve a target level of purity, for example byreturning some or all of the purified cannabinoid distillates 1120 onpath 1121 to the initial step 1101.

Purified cannabinoid distillates 1120 may then be input into blendingprocess 111 (to add terpenes, for example); in one or more embodiments,the purified cannabinoid distillates 1120 may be used directly as afinal product, or they may be further processed in any desired manner.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

What is claimed is:
 1. A method for removing contaminants fromcannabinoid distillates to yield purified cannabinoid distillatesconsisting essentially of: obtaining cannabinoid distillatesadditionally consisting essentially of one or more contaminants;  mixingsaid cannabinoid distillates additionally consisting essentially of saidone or more contaminants with ethanol and distilled water to yield acannabinoid-ethanol-water solution;  allowing said one or morecontaminants to settle out of said cannabinoid-ethanol-water solution; separating said cannabinoid-ethanol-water solution into a purifiedcannabinoid-ethanol-water solution and residual contaminants separately; distilling said ethanol and said distilled water from said purifiedcannabinoid-ethanol-water solution to yield purified cannabinoiddistillates;  wherein the mixing of said cannabinoid distillates withsaid ethanol and said distilled water to yield saidcannabinoid-ethanol-water solution consists essentially of adding saidethanol to said cannabinoid distillates at a ratio between 2:1 and 4:1of ethanol by volume in mL to cannabinoid distillates by mass in grams,to yield a cannabinoid-ethanol solution; heating saidcannabinoid-ethanol solution to a temperature between 40° C. and 80° C.to yield a dissolved cannabinoid-ethanol solution; adding said distilledwater to said dissolved cannabinoid-ethanol solution at a ratio between1:4 and 1:10 of said distilled water by volume in mL to said cannabinoiddistillates by mass in grams, to yield said cannabinoid-ethanol-watersolution; and, heating said cannabinoid-ethanol-water solution to atemperature between 40° C. and 60° C.; and, wherein the allowing saidone or more contaminants to settle out of said cannabinoid-ethanol-watersolution consists essentially of cooling said cannabinoid-ethanol-watersolution to a temperature between −30° C. and 10° C., yielding a cooledcannabinoid-ethanol-water solution; and, allowing said contaminants tosettle out of said cooled cannabinoid-ethanol-water solution for aperiod of time between 2 hours and 7 days.
 2. The method of claim 1,wherein said one or more contaminants are water-soluble.
 3. The methodof claim 1, wherein said one or more contaminants consists essentiallyof one or more of pesticides and fungicides.
 4. The method of claim 1,wherein said one or more contaminants consists essentially of one ormore of Abamectin, Acephate, Acetamiprid, Aldicarb, Azoxystrobin,Bifenazate, Boscalid, Carbaryl, Carbofuran, Chlorpyrifos, Daminozide,Dichlorvos, Dimethoate, Ethoprophos, Fenarimol, Fenchlorphos,Fenhexamid, Fenoxycarb, Fipronil, Flonicamid, Fludioxonil, Fonofos,Imazalil, Imidacloprid, Iprodione, Kresoxim-methyl, Malathion,Metalaxyl, Methiocarb, Methomyl, MGK-264, Myclobutanil, Naled, Oxamyl,Paclobutrazol, Parathion, Phosmet, Piperonyl butoxide, Pirimiphos,Prallethrin, Promecarb, Propiconazole, Propoxur, Pyraclostrobin,Spinetoram, Spirotetramat, Spiroxamine, Tebuconazole, Thiacloprid, andThiamethoxam.
 5. The method of claim 1, wherein said separating saidcannabinoid-ethanol-water solution into said purifiedcannabinoid-ethanol-water solution and said residual contaminantsseparately consists essentially of one or more of pouring said purifiedcannabinoid-ethanol-water solution off of said cannabinoid-ethanol-watersolution; siphoning said purified cannabinoid-ethanol-water solution offof said cannabinoid-ethanol-water solution; and, filtering said residualcontaminants out of said cannabinoid-ethanol-water solution to yieldsaid purified cannabinoid-ethanol-water solution.
 6. The method of claim1, wherein said removing said ethanol and said water from said purifiedcannabinoid-ethanol-water solution to yield said purified cannabinoiddistillates consists essentially of one or more of heating said purifiedcannabinoid-ethanol-water solution to cause said ethanol and said waterto evaporate, leaving said purified cannabinoid distillates; and,distilling said purified cannabinoid-ethanol-water solution to recoversaid purified cannabinoid distillates.